Spiraeoside extracted from red onion skin ameliorates apoptosis and exerts potent antitumor, antioxidant and enzyme inhibitory effects

Red onion skin waste (ROSW) was analyzed for extraction of naturally occurring 4 ' -O-glucoside of quercetin, spiraeoside (SPI) with promising biological activities. Reversed-phase high-performance liquid chromatography was used to determine the SPI content in three different solvent extracts of ROSW: water (12.2 mg/g), methanol (27.6 mg/g), and ethanol (32.5 mg/g). The ethanol extract and SPI showed significant radical-scavenging and anti-inflammatory activities. In addition, the anti-cancer effects of SPI on a HeLa cells was investigated. The results indicated that SPI treatment significantly inhibited cell growth, and the dose of 50 mu g/mL exhibited the highest anti-cancer activity. SPI inhibited the expression of B-cell lymphoma 2 and BH3-interacting domaindeath agonist and promoted apoptosis by activating caspase-9/-3 expression. Notably, SPI inhibited the expression of mu-2-related death-inducing gene, a molecule involved in death receptor-mediated apoptotic signaling. Cyclin-dependent kinase 2-cyclin-E expression was also inhibited after SPI treatment, particularly at the G2/M checkpoint. Our findings provide novel insights into the apoptotic potential with promising anticancer and enzyme inhibitory effects of ROSW SPI.

Automated summary

The study analyzed the red onion skin waste (ROSW) for the naturally occurring 4 '-O-glucoside of quercetin, spiraeoside (SPI), which showed promising biological activities. The ethanol extract of ROSW and SPI exhibited significant radical-scavenging, anti-inflammatory, and anti-cancer activities by inhibiting cell growth and promoting apoptosis. Notably, SPI also inhibited the expression of molecules involved in apoptotic signaling, showing novel insights into its potential as an anticancer agent.